Then &Now

Darwin, DNA, and The Genome
Milestones in the Evolution of Genetic Research

2009 marks the 200th anniversary of Charles Darwin's birth and the 150th anniversary of the publication of his groundbreaking work, The Origin of Species. Since that time, many more scientific milestones have occurred in our understanding of evolution and genetics.

1809:

Charles Darwin, the Father of Evolution,
is born.

1859:

Darwin Publishes On the Origin of Species

Radical in sweep, Darwin's On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life forces a rethinking of humankind's place in the natural world. Darwin ends his groundbreaking book with these words:

"…There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved."

— Charles Robert Darwin,
from On the Origin of Species (1859)

Darwin studies inheritance in organisms from peas to pigeons and produces variations over generations. But he does not know why living things resemble their parents or display certain traits.

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other living things. Our genetic "code" is assembled from four chemicals: adenine (A), guanine (G), cytosine (C), and thymine (T). The order, or sequence, of these chemicals determines how an organism will be built and maintained—similar to how letters of the alphabet may be combined to form words and sentences.

2003:

Human Genome Sequenced

Begun in 1990 and completed in 2003, the Human Genome Project now gives us the ability, for the first time, to read nature's complete genetic blueprint for building a human being. Sponsored by the U.S. Department of Energy and the NIH, the project has created the field of genomics—understanding genetic material on a large scale—and jump-started what some call the "biology century." Scientists are building on the knowledge, resources, and technologies resulting from the Human Genome Project to better understand genetic contributions to human health. As a result, the field of genomic medicine was born. Genetics is playing an increasingly important role in how we diagnose, monitor, and treat diseases.

Evolution in Medicine:

Combating New Infectious Diseases

In late 2002, several hundred people in China came down with a severe form of pneumonia caused by an unknown infection. Called "severe acute respiratory syndrome," or SARS, the disease soon spread to Vietnam, Hong Kong, and Canada and led to hundreds of deaths. In March 2003, a team of researchers at the University of California, San Francisco, received samples of a virus isolated from the tissues of a SARS patient. Using a new technology known as a DNA microarray, within 24 hours the researchers had identified the virus as a previously unknown member of a particular family of viruses—a result confirmed by other researchers using different techniques. Immediately, work began on a blood test to identify people with the disease (so they could be quarantined), on treatments for the disease, and on vaccines to prevent infection with the virus.

The Find Out More

An understanding of evolution was essential in identifying the SARS virus. The genetic material in the virus was similar to that of other viruses because it had evolved from the same ancestor virus. Also, knowing the evolutionary history of the SARS virus gave scientists important clues about the disease, such as how it is spread. Knowing the evolutionary origins of human infectious agents will be critical in the future as existing agents evolve into new and more dangerous forms.